This application is related to and claims the benefit of priority from French Patent Application No. 01 06826, filed on May 23, 2001, the entirety of which is incorporated herein by reference.
The present invention relates to an equipment box, in particular a splice box.
More precisely, the invention relates to an equipment box, in particular a splice box, having an orifice for inserting a cable, either in a through configuration or in a bight configuration, the orifice being associated with a closure portion for closing the orifice in leaktight manner and being provided with means for receiving conventional leaktight fixing members for a cable.
The boxes that contain the fittings needed to connect cables to equipment at determined locations along cables are conventionally designed to be leaktight. It is advantageous to preserve as much is possible the continuity of electrical and/or optical conductors in a cable having tapping points made along it for connection to equipment. This leads to leaktight boxes being provided that allow a cable to pass in a through configuration via two orifices made in two opposite walls of a box, or a cable to pass in a U-shaped or xe2x80x9cbightxe2x80x9d configuration via a single opening.
Boxes arranged for a through configuration generally have the two orifices needed for passing the cable formed in the vicinity of a junction between two separable portions of the box, for example in the form of notches opening out into a bearing zone where a lid bears against a case of the box.
It is then possible to insert a cable so that it passes through the box via the notches without it being necessary to thread one end of the cable through an orifice, which rapidly becomes unacceptable once the cable is of significant length. Furthermore, it commonly happens that such a box is used to establish distribution from a fixed cable that has already been installed, which makes it necessary to be able to put the box into place without moving the cable.
Making a leaktight box including a cable passage that opens out to a junction zone between portions of the box requires sealing means to be installed in order to guarantee leaktightness in the zone where the cable meets the two portions of the box.
European patent document EP 0 942 507 describes such a sealing device for a straight cable in a semi-tubular access, the device sealing the box at the access opening. That device includes an additional cover member which is provided both with a longitudinal rib for closing the semi-tubular access, and with a transverse groove on the rim for receiving a peripheral gasket, cable packing, and a front cable guide that receives thrust from a presser member acting on the packing.
It is difficult to obtain and to conserve so-called xe2x80x9ctriple pointxe2x80x9d sealing between the elements constituting the cable and the two meeting portions of the box, because of the need for those elements to co-operate with one another, in particular by being in alignment, and specifically in the box that is opened again at a later date.
Boxes that are arranged to receive a bight of cable generally have an elongate opening formed in a wall of the case for receiving a U-shaped bight of the cable inside the box. The periphery of such an opening forms a gasket-bearing surface, and it is surrounded at each end by a respective external entry tube carried by the box. During assembly, the opening is closed by a gasket comprising a strip for closing the opening together with two perforated tubular pads projecting from the ends of the strip.
European patent document EP 0 942 506 discloses such a sealing device for a bight of cable received in a box through a peripherally closed access provided with two facing and spaced-apart semi-tubular portions of entry tube. The sealing device comprises a single gasket for sealing both sections of the bight of cable inside the access, and pressure-applying means adapted to close the entry tube portions and to press against the gasket so as to obtain the desired sealing effect.
Such as sealing device requires a gasket of special shape in order to be able to close and seal said access.
The object of the invention is to provide a sealing device which enables a conventional cable joint to be used, i.e. a split cylinder, regardless of whether the cable is in a through or a bight configuration.
The invention provides an equipment box, in particular a splice box, having an orifice for inserting a cable disposed in a bight configuration, the opening being associated with at least one leaktight closure portion for this orifice provided with entry tube means for receiving conventional leaktight fixing members for a cable, said closure portion being complementary in shape to the orifice and being provided with an overmolded gasket co-operating with a gasket-bearing surface on a portion of the box, the box being characterized in that said insertion orifice is elongate in shape, being provided in a wall of the box, and is surrounded by a bearing surface for a gasket, and said closure portion is constituted by two identical parts which, when assembled together, form a closure wall for said orifice, which wall carries two entry tubes for receiving conventional leaktight fixing members for a cable and carries on its periphery an overmolded gasket.
In a preferred embodiment, each of said identical parts constitutes a half-wall provided with two half entry tubes.
Preferably, said identical parts are provided on their adjoining edges with respective overmolded gaskets and with means for positioning by mutual engagement.
The invention also provides an equipment box, in particular a splice box, having an orifice for inserting a cable disposed in a through configuration, the opening being associated with at least one leaktight closure portion for this orifice provided with entry tube means for receiving conventional leaktight fixing members for a cable, said closure portion being complementary in shape to the orifice and being provided with an overmolded gasket co-operating with a gasket-bearing surface on a portion of the box, which box comprises an open first portion or xe2x80x9ccasexe2x80x9d with an opening closed by a second portion or xe2x80x9clidxe2x80x9d that bears against a gasket positioned at the margin of the opening, the box being characterized in that said insertion orifice is in the form of a notch made in the margin of the case and is provided at the bottom of the notch with a segment of entry tube, and said closure portion comprises a complementary segment of entry tube and a wall for closing said notch, said wall carrying an overmolded gasket designed to be received in a bearing zone of the lid.
In a preferred embodiment, said gasket is a segment of O-ring gasket whose ends are designed to be received in a groove in the box and are placed end to end with gasket segments in order to provide sealing between the box and the lid.
Preferably, said gasket is an O-ring designed to be received in a groove of the box in order to provide sealing between the box and the lid.
Advantageously, said closure portion is provided on its edges meeting said insertion orifice with overmolded gaskets.
Said closure portion can be made out of the same material as the box and it can be assembled to the box by screws.
In this way, once the closure portion has been mounted in the insertion orifice, it completes the box in conventional manner, forming at least one entry tube fixed thereto and receiving a cable in leaktight manner by a conventional assembly comprising packing, a cable guide, and a packing box or presser.
Standard split packing can be used. Similarly, the cable guide and the packing box used for fixing the cable in the entry tube in leaktight manner are quite conventional.
Furthermore, this type of arrangement is equally suitable for mounting a cable in a through configuration or in a bight configuration. The same assembly of packing, a cable guide, and a packing box can be used in both cases. This greatly reduces the cost of fittings, since only one kind of sealing kit is needed.
In addition, such an arrangement makes it possible to provide sealing outside the box rather than inside, and consequently sealing can be obtained over a broad range of cable diameters up to diameters that are large.
Finally, an overmolded gasket provides excellent sealing while also making assembly easier.